SQL REPLICATE - weird results -

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perhaps i've been @ few many hours, there odd results of statement.

the result of statement

(1) datalength(rtrim([last name])) last_name_length

is 10.

the result of next statement, want use padding last_name column spaces,

(2) datalength(replicate(' ', (30 - datalength(rtrim([last name])))))

is 20.

you think result of statement,

(3) datalength(rtrim([last name]) + replicate(' ', 30 - datalength(rtrim([last name]))))

would 30.

it isn't. it's 50. result of statement (3) consistently greater of statement (2) 30. it's if i'm using + operator in replicate statement instead of -.

i've googled again , again , don't see what's wrong syntax. appreciated.

it looks want pad 30 chars, use str

select str([last name], 30)

original answer below

can replicate issue

declare @last_name nvarchar(30) set @last_name = '12345' select     datalength(rtrim(@last_name)) last_name_length,     datalength(replicate(' ', (30 - datalength(rtrim(@last_name))))),     datalength(rtrim(@last_name) + replicate(' ', 30 - datalength(rtrim(@last_name))))

output

last_name_length              ---------------- ----------- ----------- 10               20          50

to fix it, using len doesn't work, results in (because trailing spaces not counted)

last_name_length              ---------------- ----------- ----------- 5                0           5

instead, divide datalength results 2

declare @last_name nvarchar(30) set @last_name = '12345' select     datalength(rtrim(@last_name))/2 last_name_length,     datalength(replicate(' ', 30 - datalength(rtrim(@last_name))))/2,     datalength(rtrim(@last_name) + replicate(' ', 30 - datalength(rtrim(@last_name))/2))/2

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